Flotation reagent



United States Patent Ofitice FLOTATION REAGENT No Drawing. Application December 12, 1955 Serial No. 552,247

Claims. (Cl. 2522-61) This invention relates to the concentration of ores by flotation, and has for its object the provision of a novel and improved reagent for such processes and method of making the same. The reagent of the invention behaves generally as a cationic or amine-type collector or promoter of flotation. It is of particular utility in the concentration of phosphate minerals from ores containing a siliceous gangue by any of the flotation processes, such as froth flotation, skin flotation, flotation by continuous belt and by tabling processes, and the like.

The reagent of the invention is a polymerization condensation reaction product resulting from heating a mixture containing (1) from 2.5 to 18 molecular equivalents of a commercially crude heterogeneous product such as crude tall oil, tall oil pitch or equivalent crude fatty product of vegetable or animal origin and (2) one molecular equivalent of a commercial alkylene polyamine or a polyalkylene polyamine, herein collectively referred to as a commercial polyamine. Preferably the two reacting components are tall oil pitch, or crude tall oil, and commercial diethylene triamine. The reaction is effected by rapidly heating a mixture of the two reacting components to a temperature of 300 to 425 F. in an open reactor at atmospheric pressure. The structure of the reaction product is not known and no attempt has been made to determine its structure since the initial starting components are crude heterogeneous mixtures of various compounds and no specifically pure starting component will yield reaction products having the desirable properties of the reagent of the invention.

The reagent of the invention acts with greater rapidity than any prior art reagent in furthering a separation of similar ore constituents. It is equally well suited for a bulk silica removal or for the double float practice currently in general use in the Florida phosphate field. In the double float practice, the phosphate-bearing ore is prepared for concentration by various washing and sizing operations to remove colloidal material (slimes) and oversize particles which, if not removed, interfere with the flotation operation. The so sized ore is mixed and conditioned with the proper quantities of a fatty acid, fuel oil and caustic soda, and is subjected to flotation in which the bulk of the phosphate values are removed in the froth (phosphate rougher concentrate). The phosphate float is deoiled by agitating with about 2 pounds of concentrated sulfuric acid per ton of concentrate in a slurry of from 20 to 50% solids, and is then dewatered, thoroughly rinsed and again dewatered, thus removing practically all of the residual reagents from previous treatments. The deoiled and deacidified rougher concentrate is then fed to the so-called amine or cleaner circuit where by the aid of the reagent of the invention a silica-bearing froth is removed which is characterized by unusually large agglomerates of gangue material and silica. In the phosphate field, it is customary to call the phosphate product concentrate, regardless of whether it is the floated product or the underflow of the flotation Patented Oct. 21, 1958 apparatus, and hence the silica float is designated as tailings.

The reagent of the invention is derived from crude tall oil, tall oil pitch, or similar vegetable or animal oil distillation (still) residues and pitches including cottonseed oil pitch and residues from fat or grease recovery processes. Except for crude tall oil these fatty products are relatively surplus or waste materials finding but little application at present in industry. Distilled or purified oils are not desirable raw materials for the preparation of our reagent since reaction products similarly made therefrom do not exhibit the characteristics or the potency of the reagent of the invention made from one of the aforementioned crude fatty products.

Crude tall oil is obtained as a by-product in the manufacture of paper and is well known in industry. Its composition varies somewhat in difierent localities in that more or less rosin acids are present and due to this difference the ratio of other compounds in the tall oil changes accordingly. The composition of an average tall oil is about 40 to 50% fatty acid mixture, consisting of saturated and unsaturated acids, and from 50 to 60% rosin acid mixture, and from 2 to 8% of a mixture of unsaponifiable material. The fatty acid mixture consists of oleic, linoleic, traces of linolenic, palmitic, stearic, lignoceric and cerotic acids. The rosin acid mixture is composed of abietic acid, neoabietic acid, dihydroabietic acid, tetrahydroabietic acid, dehydroabietic acid, dextropimaric acid and isodextropimaric acid. The mixture of unsaponifiables consists of hydrocarbons, long chain alcohols and sterols. The hydrocarbon fraction consists of abietenes and diterpenes, and the long chain alcohols are predominantly lignoceryl alcohol.

Components in tall oil pitch are about the same as in crude tall oil but in different proportions. In the pitch there are from 30 to 40% unsaponifiables and only from 40 to 60% combined rosin acids and fatty acids along with minor amounts of polymerization products. Other pitches, still residues, oil foots and the like, of vegetable or animal origin, are of similar nature in that only small percentages of fatty acids are present. In these products the other constituents do not usually include any rosin acids but are instead polymerization products and other non-saponifiable materials.

For economic reasons the preferred polyamine used in the preparation of our reagent is commercial diethylene triamine which also contains minor amounts of triethylene tetramine, tetraethylene pentamine and ethylene diamine. Any commercial alkylene polyamine or polyalkylene polyamine is, however, suitable, and in the interest of simplicity such are herein referred to as polyamines. In preparing the reagent one molecular equivalent of the polyamine is reacted with from 2.5 to 18 molecular equivalents of the fatty product, based on an average combining weight of 340 for the fatty product, which is the combining weight of most crude tall oils and close to the combining weight of tall oil pitch and equivalent crude fatty products. Reacting diethylene triamine with the fatty product, we have found a molar ratio of 1 to 2.5-6 to be the most advantageous, and when reacted with tall oil or tall oil pitch excellent results have been obtained with a molar ratio of 1 to 3. Reacting triethylene tetramine with the fatty product, from 2.5 to 12 molecular equivalents of fatty product for each molecular equivalent of this polyamine is preferable, and with tetraethylene pentamine from 2.5 to 18 molecular equivalents of fatty product may advantageously be reacted with one molecular equivalent of the polyamine.

According to our present preferred method of preparing the new reagent, 9 parts by weight (i. e. 3 molecular equivalents) of tall oil pitch (or tall oil or equivalent crude fatty product) are thoroughly mixed with 1 part by weight (i. e. 1 molecular equivalent) of crude commercial diethylene triamine at a temperature just high enough to melt the pitch (or at room temperature if liquid reactants are used). This mixture is heated as rapidly as possible and quickly attains a temperature of 240 F. Water then begins to come off and the temperature rises more gradually to 315 F. with some frothing of the reacting mixture. At 315 F. the temperature again begins to rise rapidly, and at 400-425 F. the reaction is substantially complete and the reagent is ready for use.

The reagent is insoluble and non-dispersible in water, and hence is customarily used in solution in a suitable hydrocarbon distillate, such as kerosene, or in any one of the commonly-used frother alcohols. In addition to kerosene, other hydrocarbon distillates such as benzol, naphtha, fuel oil, and the like may be equally well used as solvents. Suitable frother alcohols are di-isobutyl carbinol, methyl isobutyl carbinol, mixed primary amyl alcohols, and the like. The frothing quality of the alcohol is not a required characteristic in mixtures of the new reagent therewith, since the reagent serves equally well where no type of frother is present. The new reagent does not itself possess any frothing characteristic, and its activity and efliciency as a cationic flotation collector or promoter are primarily due to its unusually strong agglomerating action and the rapidity with which agglomerates are formed.

In order to facilitate solution, the hot reagent is run into the solvent (e. g. kerosene) in which it is intended to be used as soon as it has cooled sufliciently to prevent any hazard from combustion of the solvent, and is made up to the desired concentration in the solvent, generally in the proportion of from to 60% by weight of reagent to 90 to 40% by weight of solvent. The preferred range of pH of the reagent or of the reagent in a neutral solvent is from 7.4 to 8.4, more specifically 8.25 pH, as a silica collector in the separation of silica from phosphate in flotation processes, although in the flotation treatment of other ores the pH of the reagent may vary from 7 to 9. The cool reaction mixture, when not diluted with solvent while hot, sets to a hard and difiicultly-soluble mahoganycolored solid. For this reason it is preferred to dilute the hot reaction product with at least a portion of the solvent. When the reagent-solvent mixture is made up to contain 1 part of reagent and 4 parts of kerosene, a reagent mixture results which, when applied as the collector-promoter in the cleaner or amine circuit of the double-float phosphate flotation process, yields a superior performing collector which rapidly agglomerates the particles of silica, silicates, heavy minerals and other gangue materials into a tightly agglomerated overflow froth.

Although it is preferred to use reactants which do not contain water, the fact that tall oil usually contains water and commercial ethylene diamine, for example, contains from to 40% water in no way interferes with the preparation of the reagent. This water is generally expelled during the reaction, passing off at a temperature below 260 F., at which temperature water formed by the reaction itself begins to pass off.

In order to facilitate the handling of pitches, still residues, and even crude tall oil, these may be cut or diluted with a fluid fuel oil of, for example, API, kerosene or other suitable petroleum distillate, and in the cases where these are not desirable with any other high boiling point diluent. The polymerization condensation reaction is then carried out in the presence of the diluent which has the beneficial effect of reducing froth during the reaction. The final temperature of reaction is not altered and an equally potent and efiicient reagent is produced by this procedure which has the further advantage of permitting pumping of both reacting materials.

Dilution may be to the extent of 50% of the pitch (or other residual product) used, in which case of course the ratio of pitch plus diluent to polyamine is increased twofold. When the reagent (reaction product) is prepared with a mixture of fuel oil (or other diluent) and pitch (or other residual product) and is made into a reagentsolvent mixture for use in the flotation process, the quantity of fuel oil (or other diluent) present is considered as part of the required kerosene (or other reagent-solvent), since the pitch-diluent and reagent-solvent function similarly in the flotation process.

Close pH control in the preparation of the reagent is very important, but after the reagent (or a solution thereof in a neutral solvent) has been prepared with a pH within the aforementioned ranges, the pH of the mineral pulp to which it is added as a silica collector may vary within the range of 6 to 9. For example, the deoiled and deacidified phosphate rougher concentrate in the double float practice customarily has a pH around 6.5 (and occasionally even lower), and when diluted with water of a pH around 7.2 gives a mineral pulp whose pH is in the neighborhood of 7. The agent of the invention having a pH between 7.4 and 8.4 (and preferably about 8.25 at which pH optimum separation is attained) functions particularly well as a silica collector in such a pulp. On the other hand, the potency of the reagent is sharply reduced by treatment thereof with a strong mineral acid. Moreover, the potency of the reagent as a silica collector decreases when the pH of the mineral pulp undergoing flotation is about 9 and higher. In a mineral pulp having a pH of about 10 and higher, the polarity of the reagent reverses and it becomes a collector for phosphate values.

The fact that the reagent can be used to float either silica or phosphate values by control of the pH and conditioning of the mineral pulp undergoing flotation is one of its startling characteristics. When a silica-bearing froth produced with the reagent of the invention is collected, dewatered and conditioned in a thick pulp of from 40 to 70% solids in the presence of sufficient sodium hydroxide (NaOH) solution to produce a pH of from 10 to 14 (and more specifically 12.5) and from 0.3 pounds to 2.0 pounds of fuel oil per ton of dry solids in the froth, and this mixture is conditioned for from 15 to seconds and again subjected to a flotation process, the polarity of the collector reagent reverses, and a phosphate-bearing froth is collected while most of the silica, silicates, heavy minerals and other gangue materials remain in the flotation cell. The reagent cannot be regenerated to a silica collector no matter what pH is given the pulp. Thus, when the floated phosphate-bearing material is again brought to a pH of 6.5 to 7.5 and refloated, the residual silica, silicates, heavy minerals and other gangue materials drop out in the tailings and a high grade phosphate froth is produced. Other variations of pH yield more or less contaminated products.

The fact that our new reagent is readily produced from the very cheapest and crudest raw materials make it very attractive from an economic standpoint. At the present time the new reagent compares very favorably with any of the cationic collectors now being marketed, in efficiency as well as selectivity in the flotation processes in which they are employed. Its cost, however, is less than one fourth that of the cheapest cationic collector-promoter currently on the market. In many cases the poundage of the new reagent required per ton of ore treated is only about 50% of that required when a presently available commercial cationic collector is used. The fact that the new reagent can be used in kerosene as a solvent makes it additionally attractive in that kerosene is probably the cheapest available solvent for a collector-promoter of this general type. In addition to kerosene, the reagent may be dissolved in any other suitable hydrocarbon distillate or frother alcohol.

We are aware that cationic flotation reagents have heretofore been prepared by reacting a polyalkylene polyamine with a fatty acid, fatty acid glyceride or other ester, usually in a mol to mol ratio, at a temperature in excess of 250 C., which is very near the cyclization point, even though cyclization is not complete below 280 C. Our reagent is formed far below the temperature where any cyclization takes place. The prior art reactants are substantially pure compounds, as contrasted with the crude heterogeneous mixtures and commercial grades of polyamine used in the preparation of our reagent. The molar ratio of fatty product to polyamine in our reagent (at least 2.5 to 1, preferably 3 to l, and as high as 18 to 1) is higher than that of the corresponding reactants of the prior art reagents. The selectivity of our reagent increases with increase in the molar ratio of fatty product to polyamine. The prior art reagents do not possess the distinctively desirable and advantageous properties that characterizeour reagent.

Our reagent is neither soluble nor dispersible in water, is incapable of forming acid addition salts, and is almost completely deactivated by concentrated sulphuric acid. The prior art reagents are water soluble or water dispersible, combine with acids to yield water soluble salts, and for the most part their flotation properties are enhanced'by treatment with concentrated sulphuric acid. The prior art reagents are not reversible in polarity, while the polarity of our reagent can be reversed by pH adjustment of the mineral pulp undergoing flotation. The amine-type flotation agents presently available have molecular weights not exceeding about 900, while the reaction product reagent of the invention has a molecular weight of from 1000 to 6000, based on a combining weight of 340 forthe fatty product.

The following examples, illustrating various embodiments of the invention, show the effectiveness of the new reagent with phosphate ore, in the concentration of which the reagent makes possible a superior and more economic concentration in a froth of the gangue materials and silica. In all examples only the actual amount of the reagent (collector) is reported. The amount of reagent-solvent mixture may be readily calculated from the ratio of reagent to solvent in the mixture. Except as otherwise noted the tests were carried out in a laboratory size Fagergren flotation machine, silica, silicates, heavy minerals and other gangue materials being floated and reported as tails. The examples are in no may to be construed as limiting the scope of the invention.

EXAMPLE 1 The reagent used was prepared from 72 grams of crude tall oil and 8 grams of commercial diethylene triamine; a molar ratio of approximately 3 to 1. The two reactants were mixed cold and when thoroughly mixed the mixture was rapidly heated to 400 F. The hot reaction product (reagent) was diluted with kerosene to produce a mixture of 20% reagent and 80% kerosene and was so used in the tests.

The deoiled rougher flotation concentrate which was used as feed analyzed 70.69% BPL (bone phosphate of lime) and 12.56% silica determined (as customary in the phosphate industry) as insolubles.

The reagent used was the same as in Example 1, but in a mixture of 30% reagent and 70% kerosene. The

feed was a deoiled rougher flotation concentrate as in Example 1. 3

Cone.

Tails, Percent Reagent, Test N 0. Percent BPL lbs./ton

Percent I Percent BPL Recovery Conc.

BPL Insol.

This reagent mixture handles well and it will be noted that an appreciable decrease in phosphate value in the tails is obtained.

EXAMPLE 3 The reagent used was the same as in Example 1, but in a mixture of 40% reagent and 60% kerosene. The feed was again a deoiled rougher flotation concentrate as in Example 1.

The reagent used was the same as in Example 1, but in a mixture of 50% reagent and 50% kerosene. This resulted in a very viscous difiiculty pumpable reagent mixture and results are not improved by the heavy concentration of reagent. The feed was the same as in Example 1.

Cone.

Tails, Percent Reagent, Test N0. Percent BPL lbs./t0n

Percent Percent B L Recovery 0011c.

BPL Insol.

EXAMPLE 5 The tests of the foregoing examples were carried out in a laboratory flotation machine. The tests of the pres ent example were conducted on a commercial plant scale. The reagent used was the same as in Example 1, in a mixture of 20% reagent and kerosene. The feed was a deoiled rougher flotation concentrate having an average analysis of 74.53% BPL and 7.33% insolubles.

Oonc.

Tails, Percent Reagent, Test N0. Percent BPL lbs/ton Percent Percent BPL Recovery Cone.

BPL Insol.

EXAMPLE 6 sieve to remove the oversize. It analyzed 23.58% BPL and 68.03% insolubles, and was used without additional treatment or conditioning.

Cone.

Tails, Percent Reagent, Percent BPL lbs/ton Percent Percent BPL Recovery Cone.

BPL Insol.

The new reagent showed excellent potency in upgrading the phosphatic material.

No attempt was made in this test to produce a finished concentrate. The purpose of the test was to illustrate the effectiveness of the new reagent in producing a rougher concentrate by making a bulk silica removal. This rougher concentrate is comparable to that obtained in the present conventional fatty acid-fuel oil-caustic float, but does not require the costly deoiling step.This effects a noteworthy saving in that no sulfuric acid is required and no attrition loss occurs. The rougher concentrate from the bulk silica removal can be directly transported to the cleaner circuit for removal of residual silica, without even dewatering, in a properly planned flow sheet.

EXAMPLE 7 In order to illustrate the effectiveness of the new reagent in a solvent other than kerosene, the reagent was made up in a 50/50 mixture with Acintene C a sulfated turpentine product produced by Arizona Chemical Company. Acintene C has no collector properties, but does exhibit frothing qualities. The reagent used was the EXAMPLES 8 TO 11 These examples show the results of several days continuous plant run of phosphate flotation using the new reagent prepared in a ratio of 9 parts crude tall oil and 1 part commercial diethylene triamine. Feed to the amine flotation section of the plant consisted of a rougher phosphate flotation concentrate obtained by the present conventional fatty acid-fuel oil-caustic process. This rougher phosphate concentrate was thoroughly deoiled by agitation in the presence of sulfuric acid and then rinsed thoroughly with water. The feed was then subjected to a cleaner flotation step using the new reagent in a mixture of reagent and 80% kerosene. Asilica-bearing froth was removed and a finished phosphate concentrate was continuously discharged in the underflow. The feed had an average analysis of 72.28% BPL and 10.73% insolubles.

8 EXAMPLE 12 The reagent was made by heating a mixture of 70 parts of tall oil pitch and 8.5 parts of commercial diethylene triamine to 400 F. where the reaction is complete. The reagent was used in a mixture of 70% kerosene and 30% reagent in the amounts noted. In Part I, the feed Was a raw phosphate ore analyzing 39.40% BPL and 49.61% insolubles which had been previously deslimed, and in Part II, the feed was a deoiled rougher phosphate concentrate analyzing 74.64% BPL and 7.40% insolubles.

Part I Cone.

Tails, Percent Reagent, Test N 0. Percent BPL lbs/ton Percent Percent BPL Recovery Cone.

BPL Insol.

Part II Cone.

Tails, Percent Reagent, Test No. Percent BPL lbs/ton Percent Percent BPL Recovery Cone.

BPL Insol.

EXAMPLE 13 This example illustrates the efiect of one of the frother alcohols on the float when the new reagent is used as a collector. It will be noted that the frother alcohol does not promote the float. The reagent was the same as used in Example 12, except that it was used in a mixture of 50% reagent and 50% di-iso-butyl carbinol. The feeds in Parts I and II were the same as in Parts I and II, respectively, of Example 12.

Part 1 Cone.

Tails, Percent Reagent, Test N 0. Percent BPL lbs/ton Percent Percent BPL Recovery Cone.

BPL Insol.

Part 11 Cone.

Tails, Percent Reagent, Test No. Percent BPL 1bs./ton

Percent Percent BPL Recovery Cone.

BPL Insol.

EXAMPLE 14 The reagent used in this example was prepared by reacting 72 parts of a grease recovery residue pitch with 8.5 parts of diethylene triamine at 400 F. The reaction product was made into a fluid mixture with kerosene in the proportions of 30% reagent and kerosene. The

feed was a deoiled rougher phosphate concentrate analyzing 74.64% BPL and 7.40% insol.

Cone.

Tails, Percent Reagent, Test No. Percent BPL lbs/ton Percent Percent BPL Recovery Cone.

BPL Insol.

EXAMPLE 15 This example illustrates the unique characteristic of the reagent of polarity reversion; the reagent acting first as a silica collector and then as a phosphate collector.

A raw feed which had been thoroughly deslimed and then screened to remove all plus 14 mesh material was used in the tests. The feed analyzed 39.55% BPL and contained 49.39% insolubles. I

The feed was weighed into a laboratory flotation cell and the pulp diluted to approximately solids. The reagent used in test No. 1 was prepared from tall oil pitch (and in tests Nos. 2, 3 and 4 from tall oil) and commercial diethylene triamine in molecular equivalents of approximately 3 to 1, respectively, and in all tests was used in a mixture of 30% reagent and 70% kerosene.

pH of the raw feed was 7.70 and after the addition of reagent increased to 7.78. The pulp and reagents were conditioned with air off for 3 seconds in order to difiuse the reagent through the pulp, then air was admitted 'and a silica bearing froth was removed which was rich in phosphate, leaving the phosphate concentrate (cone. 1) in the underfiow. The froth product (orig. tails) was then dewatered to about 50% solids and transferred to a laboratory conditioner where the appropriate quantity of fuel oil (see table) and sodium hydroxide sufiicient to raise the pH to from 10 'to 14 were added and this pulp conditioned for 30 seconds, after which it was transferred to the flotation cell and a phosphate float concentrate removed leaving the silica and other gangue materials in the underfiow. This is tail I in the table and was discarded. The phosphate froth was returned to the flotation cell and its pH adjusted to from 7.0 to 8.5 with sulfuric acid and refloated to remove a phosphate float concentrate (cone. II), while in the underfiow the residual silica and other gangue materials were dropped out, constituting tails II in the table. The original tailing was calculated.

1st Float Products Refloat Products Gone. I Orig. Tails I, Tails Cone. II Test No. Tails, Per- II, Per- Percent cent Per- Percent BPL BPL Per- Percent cent BPL cent cent BPL Insol. BPL Insol Percent BPL Recovery Reagents Usedi lblliTon of Original Test Oonc. 1st Refloat Reagents N 0. Total Fllzoat NaOH I II agent Fuel H2504 Oil In test No. 4 the fuel oil contained of tall oil to EXAMPLE 16 In preparing the reagent, 96 grams (0.28 mol) of tall oil was reacted with 10 grams (0.05 mol) of tetraethylene pentamine by heating to 420 F. where the reaction was complete. The ratio of polyamine to tall oil was 1 mol to 5.6 mols. The reaction product obtained was, on cooling, a dark brown to black solid. This was made into a mixture of kerosene 70% and reagent 30%. In Part I, the feed was a raw phosphate ore which had been screened through 14 mesh and thoroughly deslimed, analyzing 38.43% BPL and 50.37% insolubles. In Part II, the feed was a deoiled rougher concentrate analyzing 72.49% BPL and 9.61% insolubles.

Part I Cone.

Tails, Percent Reagent, Test No. Percent BPL lbs/ton Percent Percent B L Recovery Cone.

BPL Insol.

Part II Cone.

Tails, Percent Reagent, Test No. Percent BPL lbs/ton Percent Percent. BPL Recovery Conc.

BPL Insol.

EXAMPLE 17 In preparing the reagent, 60 grams (0.18 mol) tall oil was reacted with 10 grams (0.07 mol) triethylene tetramine by heating to 420 F. where the reaction was complete. The ratio of polyamine to tall oil was 1 mol to 2.57 mols. The reaction product obtained was made into a mixture 70% kerosene and 30% reagent. In Part I, the feed was minus 14 mesh raw phosphate ore thoroughly deslimed, analyzing 38.43% BPL and 50.37% insolubles. In Part II, the feed was a deoiled rougher concentrate analyzing 72.49% BPL and 9.61% insolubles.

In preparing the reagent, 204 grams (0.6 mol) of tall oil Was reacted with 18.9 grams (0.1 mol) tetraethylene pentamine by heating to 425 P. where the reaction was complete. The ratio of polyamine to tall oil was 1 mol to 6 mols. The reaction product was made into a mixture Part I.-Reagent 2.15 lbs./ ton conc.

Percent Product Percent Percent BPL BPL Insol. Recovcry Concentrate 64. 50 17. 43 88. 8 Telling 4. 48 92. 34 11. 2

Part II.--Reagent 1.67 lbs./ ton cone.

Percent Product Percent Percent BPL BPL Insol. Recov- EXAMPLE 19 In preparing the reagent, 408 grams (1.2 mol) of tall oil was reacted with 18.9 (0.1 mol) tetraethylene pentamine by heating to 415 P. where the reaction was complete. The ratio of polyamine to tall oil was 1 mol to 12 mols. The reaction product was made into a mixture of 70% kerosene and 30% reagent. The feed was a raw deslimed ore screened through 14 mesh and analyzing 25.90% BPL and 66.19% insolubles. The silica froth was refloated once to produce a middling which was the underflow product.

Reagent 1.65 lb./tn conc.

Percent Product Percent Percent B]? L BPL Insol. Recov- Concentrate 61. 36 21. 84 92. 7 Middling 34. 61 54. 57 2. 7 'Iailing 1. 92 96. 48 4. 6

EXAMPLE 20 Reagent 2.76 lbs./t0n conc.

Percent Product Percent Percent BPL BPL Insol. Recovery Concentrate i 48. 64 37.03 95. 2 Middling 16.15 78. 84 1. 2 Tailing 1.88 I 96.55 as EXAMPLE 21 in preparing the reagent 204.0 grams (0.6 mol) of tall oil was reacted with 10.3 grams (0.1 mol) diethylene triamine by heating to 400 F. where the reaction was complete. The ratio of polyamine to tall oil was 1 mol to 6 mols. The reaction product was made into a mixture of 70% kerosene and 30% reagent. The feed was a 12 raw phosphate ore which had been screened through 14 mesh and then deslimed and analyzed 39.97% BPL and 49.46% insolubles. The silica froth was refloated once to produce a middling product as underflow.

Reagent 1.00 lbs./t0n cone.

The foregoing Example 15 illustrates the reversibility of our reagent by pH control of the mineral pulp undergoing flotation, thus permitting the removal of a phosphate concentrate float from the original silica (float) tailings merely by adjustment of the pH values. The same reagent used to float the silica (tailings) is used in a second flotation step to float the residual phosphate values in the silica float merely by thickening the froth somewhat, adding caustic to a high pH, adding a very small amount of fuel oil, conditioning for 30 seconds, and then floating off the phosphate. A rough pH control is all that is required. No additional collector reagent is added and the polarity of that very small quantity already on the froth particles reverses and accomplishes the second and third (cleaner) flotation steps.

We are unable to explain the mechanics of the reversibility of our reagent, although there is evidence that the reaction product (reagent) may be in the nature of a tall oil (or equivalent fatty product) salt of polyacyl diethylene triamine which is a silica collector. When a phosphate-rich silica float obtained with our reagent is made strongly alkaline with sodium hydroxide, the weak salt bond may be ruptured and the liberated tall oil may then react with the excess sodium hydroxide to form a soap on the already coated phosphate particles and at the same time deactivating the original silica collector. When a small amount of fuel oil is now added to the pulp, the soap-coated phosphate particles float free of the silica on which the reagent is deactivated. This explanation is offered without prejudice and with no intention of restricting the invention thereto.

Contrasted with comparative collectors heretofore commercially available, our reagent possesses equally good, if not better, selectivity and markedly superior potency. The superior potency of the reagent is evidenced by the rapidity with which it functions after introduction into the mineral pulp and by the smaller amount of reagent required. The low cost of the reagent itself and the decreased amount required are among its special economic advantages. Additionally, the reagent very rapidly agglomerates particles of silica, silicates, heavy minerals (e. g. ilmenite, rutile, zircon, staurolite and kyanite) and other gangue materials into a tightly agglomerated overflow froth. The rapidity with which such agglomerates are formed upon introducing the reagent into the mineral pulp accounts, we believe, for the fact that the reagent functions satisfactorily as a silica collector in neutral or even slightly acid (e. g. pH of 67) pulps, whereas close pH control of the reagent itself is important.

The pH of the reagent is determined by subjecting to the conventional method of pH measurement a mixture of equal volumes of (1) methanol and (2) a solution made up of 30% reagent and 70% kerosene. The observed pH reading of that measurement is taken as the 1 13 pH of the reagent-solvent mixture when introduced into the mineral pulp will be substantially the same as that of the reagent itself. 7

While our reagent is particularly adapted for the beneficiation of phosphate ores by flotation, it can be used with advantage in beneflciating other ores by flotation, such as iron ores, barite, calcite, feldspar, fluorspar, kyanite, industrial sands, etc.

We claim:

1. A flotation reagent comprising the polymerization condensation reaction product of from 2.5 to 18 molecular equivalents of a commercially crude product selected from the group consisting of crude tall oil and tall oil pitch reacted with one molecular equivalent of a commercial polyalkylene polyamine at a temperature of from about 300 to 425 F., and characterized by the property of being capable of exercising reversible polarity in a flotation operation by a variation in the pH of the mineral pulp undergoing flotation.

2. A flotation reagent according to claim 1 in which the polyamine is commercial diethylene triamine.

3. A flotation reagent comprising the polymerization condensation reaction product of from 2.5 to 6 molecular equivalents of a commercially crude product selected from the group consisting of crude tall oil and tall oil pitch reacted with one molecular equivalent of commercial diethylene triamine at a temperature of from about 300 to 425 F., and characterized by the property of being capable of exercising reversible polarity in a flotation operation by a variation in the pH of the mineral pulp undergoing flotation.

4. A flotation reagent comprising the polymerization condensation reaction product resulting from heating to an ultimate temperature of from about 300 to 425 F. a mixture of one molecular equivalent of commercial diethylene triamine with from 2.5 to 6 molecular equivalents of crude tall oil.

5. A flotation reagent comprising the polymerization condensation reaction product of about 9 parts by weight of tall oil pitch reacted with 1 part by weight of commercial diethylene triamine at a temperature of from about 300 to 425 F., and characterized by the property of being capable of exercising reversible polarity in a flotation operation by a variation in the pH of the mineral pulp undergoing flotation.

6. The method of preparing a flotation reagent which comprises reacting at a temperature of from about 300 to 425 F. a mixture of one molecular equivalent of a polyalkylene polyamine with from 2.5 to 18 molecular equivalents of a commercially crude product selected from the group consisting of crude tall oil and tall oil pitch, and dissolving the resulting polymerization condensation reaction product while still hot in a solvent therefor selected from the group consisting of hydrocarbon distillates and frother alcohols in the proportion of from 10 to 60% reaction product to 90 to 40% solvent.

7. The method of claim 6 in which the solvent is kerosene.

8. The method of claim 6 in which the polyamine is commercial diethylene triamine and the crude product is tall oil pitch.

9. The method of claim 8 in which the solvent is kerosene.

10. The method of preparing a flotation reagent which comprises dissolving in a hydrocarbon distillate a commercially crude fatty product selected from the group consisting of tall oil and tall oil pitch, reacting at a tem perature of from 300 to 425 F. a mixture of the resulting solution with a commercial polyalkylene polyamine in the proportion of from 2.5 to 18 molecular equivalents of the crude fatty product and 1 molecular equivalent of the polyamine, and dissolving the resulting polymerization condensation reaction product while still hot in a hydrocarbon distillate, the combined amounts of the aforementioned hydrocarbon distillates constituting from 40 to of the resulting solution of the hot reaction product.

11. A flotation reagent comprising the polymerization condensation reaction product of from 2.5 to 18 molecular equivalents of a commercially crude fatty product selected from the group consisting of crude tall oil and tall oil pitch reacted with one molecular equivalent of tetraethylene pentamine at a temperature of from about 300 to 425 F., and characterized by the property of being capable of exercising reversible polarity in a flotation operation by a variation in the pH of the mineral pulp undergoing flotation.

12. A flotation reagent comprising the polymerization condensation reaction product of from 2.5 to 12 molecular equivalents of a commercially crude fatty product selected from the group consisting of tall oil and tall oil pitch reacted with one molecular equivalent of commercial triethylene tetramine at a temperature of from about 300 to 425 F., and characterized by the property of being capable of exercisingreversible polarity in a flotation operation by a variation in the pH of the mineral pulp undergoing flotation.

13. A flotation reagent comprising the polymerization condensation reaction product resulting from heating to an ultimate temperature of about 425 F. a mixture of one molecular equivalent of commercial diethylene triamine with from 2.5 to 6 molecular equivalents of a commercially crude fatty product selected from the group consisting of tall oil and tall oil pitch, and characterized by the property of being capable of exercising reversible polarity in a flotation operation by a variation in the pH of the mineral pulp undergoing flotation.

14. The method of preparing a flotation reagent which comprises reacting at a temperature of from about 300 to 425 F. a mixture of one molecular equivalent of a polyalkylene polyamine with from 2.5 to 18 molecular equivalents of a commercially crude fatty product selected from the group consisting of crude tall oil and tall oil pitch, the pH of the reactants being controlled to impart to the reaction product a pH within the range of 7 to 9, and dissolving the resulting polymerization condensation reaction product while still hot in a substantially neutral solvent therefor selected from the group consisting of hydrocarbon distillates and frother alcohols in the proportion of from 10 to 60% reaction product to 90 to 40% solvent.

15. The method of preparing a flotation reagent which comprises dissolving in a hydrocarbon distillate a commercially crude fatty product selected from the group consisting of tall oil and tall oil pitch, reacting at a temperature of from 300 to 425 F. a mixture of the resulting solution with a commercial polyalkylene polyamine in the proportion of from 2.5 to 18 molecular equivalents of the crude fatty product and 1 molecular equivalent of the polyamine, the pH of the reactants being controlled to impart to the reaction product a pH within the range of 7 to 9, and dissolving the resulting polymerization condensation reaction product while still hot in a neutral hydrocarbon distillate, the combined amounts of the aforementioned hydrocarbon distillates constituting from 40 to 90% of the resulting solution or the hot reaction product.

References Cited in the file of this patent UNITED STATES PATENTS 2,250,176 Blair July 22, 1941 2,466,517 Blair et a1. Apr. 5, 1949 2,675,355 Lytle Apr. 13, 1954 2,708,666 Carpenter May 17, 1955 2,710,856 Carpenter June 14, 1955 2,750,339 Steinhaufi June 12, 1956 

1. A FLOTATION REAGENT COMPRISING THE POLYMERIZATION CONDENSATION REACTION PRODUCT OF FROM 2.5 TO 18 MOLECULAR EQUIVALENTS OF A COMMERCIALLY CRUDE PRODUCT SELECTED FROM THE GROUP CONSISTING OF CRUDE TALL OIL AND TALL OIL PITCH REACTED WITH ONE MOLECULAR EQUIVALENT OF A COMMERCIAL POLYALKYLENE POLYAMINE AT A TEMPERATURE OF FROM ABOUT 300 TO 425*F., AND CHARACTERIZED BY THE PROPERTY OF BEING CAPABLE OF EXERCISING REVERSIBLE POLARITY IN A FLOTATION OPERATION BY A VARIATION IN THE PH OF THE MINERAL PULP UNDERGOING FLOTATION. 